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A235100 Number of (n+1) X (1+1) 0..6 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4, with no adjacent elements equal (constant stress tilted 1 X 1 tilings). 1
154, 670, 2900, 12578, 54530, 236496, 1025770, 4449942, 19307284, 83782730, 363623322, 1578383808, 6852296402, 29752369022, 129201632884, 561144450002, 2437478108882, 10589252938544, 46009511768922, 199934061184966 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 7*a(n-1) - 2*a(n-2) - 47*a(n-3) + 3*a(n-4) + 84*a(n-5) + 36*a(n-6).

Empirical g.f.: 2*x*(77 - 204*x - 741*x^2 + 428*x^3 + 1656*x^4 + 648*x^5) / ((1 - 3*x - 6*x^2)*(1 - 4*x - 4*x^2 + 11*x^3 + 6*x^4)). - Colin Barker, Oct 17 2018

EXAMPLE

Some solutions for n=5:

..0..1....0..3....3..1....2..4....6..1....5..2....3..2....0..6....0..2....6..4

..1..6....2..1....4..6....4..2....3..2....2..3....2..5....3..5....5..3....1..3

..4..5....3..6....6..4....6..0....0..3....0..5....4..3....0..6....3..5....6..4

..5..2....1..0....1..3....3..1....5..4....2..3....6..1....2..4....0..6....4..6

..4..5....0..3....4..2....4..6....6..1....0..5....3..2....4..2....1..3....2..0

..1..6....5..4....1..3....3..1....3..2....1..2....1..4....3..5....2..0....1..3

CROSSREFS

Column 1 of A235107.

Sequence in context: A239564 A250626 A235107 * A230804 A200552 A160854

Adjacent sequences:  A235097 A235098 A235099 * A235101 A235102 A235103

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 03 2014

STATUS

approved

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Last modified January 25 01:10 EST 2021. Contains 340414 sequences. (Running on oeis4.)